The field of the invention is hardware and the invention relates more particularly to linear motion devices of the type commonly referred to as drawer slides. Precision ball bearing slides of the type shown in U.S. Pat. No. 3,205,025 utilize three standardized components comprising an outer member, a ball retainer with ball bearings and an inner member.
Typically, one of the slide members is affixed to a cabinet and the other to a drawer. In order to increase the extension of one member with respect to the other, three member drawer slides have been developed which permit full extension of the drawer from the cabinet. One configuration of a three member slide is shown in U.S. Pat. No. 3,778,120. This three member slide includes essentially two separate slides with the inner members of each slide affixed to an intermediate member so that the slide affixed to the drawer is above the slide affixed to the cabinet. A second configuration of fully extendable slides is constructed by fastening the outer web of two inner slide members and affixing one outer slide member to a cabinet and the other outer slide member to a drawer. A third configuration has a large outer slide member which has a first inner slide member which not only has a ball bearing groove on its outer edge cooperating with the large outer slide, but also has an inner facing ball bearing groove cooperating with a second inner slide member. After an extended period of use under heavy loads, even high quality slides can fail at the track of the slide member affixed to the cabinet. It has been noted that when a three member drawer slide is heavily loaded and either of the two slides is free to move that it will tend to move in a manner least adapted for long life. That is, the cabinet-mounted slide of a three member drawer slide will be extended last putting the maximum amount of strain on the outer slide member adjacent the ball retainer of the cabinet slide member.